It is known as stimulus or the plural form stimuli. It can be external or internal.
Bloodborne pathogen can be transmitted when blood or body fluid from an infected person enters another persons body via needle-sticks, himan bites, cuts, abrasions etc...
Answer:
binding of the hormone molecule with its receptor of the cell.
Explanation:
Hormones are chemical messengers secreted or released by endocrine glands to effect a response in another location called target location. Hormones are proteinous molecules and like every other protein, its function is determined by its shape.
Hormones function or effect their changes by binding to the receptor of the target cell. The hormone recognizes and will only bind to its own receptor molecule on its target cell on order to bring about any change. This defines the specificity of the hormone.
Well it really depends on what kind of change there is. For this I'll use a drought as an example. If a drought occurs in an area the plant life and vegetation will start to die off in that area. From there, primary consumers would run out of food. then secondary consumers, and so forth and so on. it'd be like putting a cow in a field of dirt with no food and a large bucket of water. Eventually the cow will die of starvation. Now apply this to all of the animals in that ecosystem.